refactor: remove visitor infavor of single converter class

Author: chr-hertel

.env

@@ -41,4 +41,4 @@ PINECONE_HOST=
 RUN_EXPENSIVE_EXAMPLES=false
 
 # For using Gemini
-GOOGLE_API_KEY=
+GOOGLE_API_KEY=

README.md

@@ -38,7 +38,7 @@ LLM Chain categorizes two main types of models: **Language Models** and **Embedd
 Language Models, like GPT, Claude and Llama, as essential centerpiece of LLM applications
 and Embeddings Models as supporting models to provide vector representations of text.
 
-Those models are provided by different **platforms**, like OpenAI, Azure, Replicate, and others.
+Those models are provided by different **platforms**, like OpenAI, Azure, Google, Replicate, and others.
 
 #### Example Instantiation
 
@@ -63,6 +63,7 @@ $embeddings = new Embeddings();
   * [OpenAI's GPT](https://platform.openai.com/docs/models/overview) with [OpenAI](https://platform.openai.com/docs/overview) and [Azure](https://learn.microsoft.com/azure/ai-services/openai/concepts/models) as Platform
   * [Anthropic's Claude](https://www.anthropic.com/claude) with [Anthropic](https://www.anthropic.com/) as Platform
   * [Meta's Llama](https://www.llama.com/) with [Ollama](https://ollama.com/) and [Replicate](https://replicate.com/) as Platform
+  * [Google's Gemini](https://gemini.google.com/) with [Google](https://ai.google.dev/) as Platform
   * [Google's Gemini](https://gemini.google.com/) with [OpenRouter](https://www.openrouter.com/) as Platform
   * [DeepSeek's R1](https://www.deepseek.com/) with [OpenRouter](https://www.openrouter.com/) as Platform
 * Embeddings Models

examples/chat-gemini-google.php

@@ -1,6 +1,6 @@
 <?php
 
-use PhpLlm\LlmChain\Bridge\Google\GoogleModel;
+use PhpLlm\LlmChain\Bridge\Google\Gemini;
 use PhpLlm\LlmChain\Bridge\Google\PlatformFactory;
 use PhpLlm\LlmChain\Chain;
 use PhpLlm\LlmChain\Model\Message\Message;
@@ -16,7 +16,7 @@
 }
 
 $platform = PlatformFactory::create($_ENV['GOOGLE_API_KEY']);
-$llm = new GoogleModel(GoogleModel::GEMINI_2_FLASH);
+$llm = new Gemini(Gemini::GEMINI_2_FLASH);
 
 $chain = new Chain($platform, $llm);
 $messages = new MessageBag(

examples/image-describer-binary-gemini.php

@@ -0,0 +1,32 @@
+<?php
+
+use PhpLlm\LlmChain\Bridge\Google\Gemini;
+use PhpLlm\LlmChain\Bridge\Google\PlatformFactory;
+use PhpLlm\LlmChain\Chain;
+use PhpLlm\LlmChain\Model\Message\Content\Image;
+use PhpLlm\LlmChain\Model\Message\Message;
+use PhpLlm\LlmChain\Model\Message\MessageBag;
+use Symfony\Component\Dotenv\Dotenv;
+
+require_once dirname(__DIR__).'/vendor/autoload.php';
+(new Dotenv())->loadEnv(dirname(__DIR__).'/.env');
+
+if (empty($_ENV['GOOGLE_API_KEY'])) {
+    echo 'Please set the GOOGLE_API_KEY environment variable.'.PHP_EOL;
+    exit(1);
+}
+
+$platform = PlatformFactory::create($_ENV['GOOGLE_API_KEY']);
+$llm = new Gemini(Gemini::GEMINI_1_5_FLASH);
+
+$chain = new Chain($platform, $llm);
+$messages = new MessageBag(
+    Message::forSystem('You are an image analyzer bot that helps identify the content of images.'),
+    Message::ofUser(
+        'Describe the image as a comedian would do it.',
+        new Image(dirname(__DIR__).'/tests/Fixture/image.jpg'),
+    ),
+);
+$response = $chain->call($messages);
+
+echo $response->getContent().PHP_EOL;

src/Bridge/Google/GoogleModel.php renamed to src/Bridge/Google/Gemini.php

@@ -6,7 +6,7 @@
 
 use PhpLlm\LlmChain\Model\LanguageModel;
 
-final readonly class GoogleModel implements LanguageModel
+final readonly class Gemini implements LanguageModel
 {
     public const GEMINI_2_FLASH = 'gemini-2.0-flash';
     public const GEMINI_2_PRO = 'gemini-2.0-pro-exp-02-05';
@@ -40,7 +40,7 @@ public function supportsAudioInput(): bool
 
     public function supportsImageInput(): bool
     {
-        return false; // it does, but implementation here is still open;in_array($this->version, [self::GEMINI_2_FLASH, self::GEMINI_2_PRO, self::GEMINI_2_FLASH_LITE, self::GEMINI_2_FLASH_THINKING, self::GEMINI_1_5_FLASH], true);
+        return true;
     }
 
     public function supportsStreaming(): bool

src/Bridge/Google/GooglePromptConverter.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Bridge\Google;
+
+use PhpLlm\LlmChain\Model\Message\AssistantMessage;
+use PhpLlm\LlmChain\Model\Message\Content\Image;
+use PhpLlm\LlmChain\Model\Message\Content\Text;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
+use PhpLlm\LlmChain\Model\Message\MessageInterface;
+use PhpLlm\LlmChain\Model\Message\Role;
+use PhpLlm\LlmChain\Model\Message\UserMessage;
+
+use function Symfony\Component\String\u;
+
+final class GooglePromptConverter
+{
+    /**
+     * @return array{
+     *     contents: list<array{
+     *         role: 'model'|'user',
+     *         parts: list<array{inline_data?: array{mime_type: string, data: string}|array{text: string}}>
+     *     }>,
+     *     system_instruction?: array{parts: array{text: string}}
+     * }
+     */
+    public function convertToPrompt(MessageBagInterface $bag): array
+    {
+        $body = ['contents' => []];
+
+        $systemMessage = $bag->getSystemMessage();
+        if (null !== $systemMessage) {
+            $body['system_instruction'] = [
+                'parts' => ['text' => $systemMessage->content],
+            ];
+        }
+
+        foreach ($bag->withoutSystemMessage()->getMessages() as $message) {
+            $body['contents'][] = [
+                'role' => $message->getRole()->equals(Role::Assistant) ? 'model' : 'user',
+                'parts' => $this->convertMessage($message),
+            ];
+        }
+
+        return $body;
+    }
+
+    /**
+     * @return list<array{inline_data?: array{mime_type: string, data: string}|array{text: string}}>
+     */
+    private function convertMessage(MessageInterface $message): array
+    {
+        if ($message instanceof AssistantMessage) {
+            return [['text' => $message->content]];
+        }
+
+        if ($message instanceof UserMessage) {
+            $parts = [];
+            foreach ($message->content as $content) {
+                if ($content instanceof Text) {
+                    $parts[] = ['text' => $content->text];
+                }
+                if ($content instanceof Image) {
+                    $parts[] = ['inline_data' => [
+                        'mime_type' => u($content->url)->after('data:')->before(';')->toString(),
+                        'data' => u($content->url)->after('base64,')->toString(),
+                    ]];
+                }
+            }
+
+            return $parts;
+        }
+
+        return [];
+    }
+}

src/Bridge/Google/GoogleRequestBodyProducer.php

@@ -31,13 +31,14 @@
     public function __construct(
         HttpClientInterface $httpClient,
         #[\SensitiveParameter] private string $apiKey,
+        private GooglePromptConverter $promptConverter = new GooglePromptConverter(),
     ) {
         $this->httpClient = $httpClient instanceof EventSourceHttpClient ? $httpClient : new EventSourceHttpClient($httpClient);
     }
 
     public function supports(Model $model, array|string|object $input): bool
     {
-        return $model instanceof GoogleModel && $input instanceof MessageBagInterface;
+        return $model instanceof Gemini && $input instanceof MessageBagInterface;
     }
 
     /**
@@ -47,13 +48,11 @@ public function request(Model $model, object|array|string $input, array $options
     {
         Assert::isInstanceOf($input, MessageBagInterface::class);
 
-        $body = new GoogleRequestBodyProducer($input);
-
         return $this->httpClient->request('POST', sprintf('https://generativelanguage.googleapis.com/v1beta/models/%s:generateContent', $model->getVersion()), [
             'headers' => [
                 'x-goog-api-key' => $this->apiKey,
             ],
-            'json' => $body,
+            'json' => $this->promptConverter->convertToPrompt($input),
         ]);
     }
 

src/Bridge/Google/ModelHandler.php

@@ -50,9 +50,4 @@ public function jsonSerialize(): array
 
         return $array;
     }
-
-    public function accept(MessageVisitor $visitor): array
-    {
-        return $visitor->visitAssistantMessage($this);
-    }
 }

src/Model/Message/AssistantMessage.php

@@ -32,9 +32,4 @@ public function jsonSerialize(): array
             ],
         ];
     }
-
-    public function accept(ContentVisitor $visitor): array
-    {
-        return $visitor->visitAudio($this);
-    }
 }